Have you noticed that you are less hungry in the summer?
It is most likely because the sun's UV rays stimulate your skin to release more of the hormone MSH - Melanocyte stimulating hormone. MSH is a group of hormones that stimulate the melanocytes to produce pigmentation and which, among other things, makes you suntanned.
In fact, it is the suntan pigmentation that protects your skin from DNA damages from the sun. But MSH also suppresses appetite by reacting with receptors in the hypothalamus in your brain. And it is most likely the reason why we eat less in the summer.
MSH hinders inflammation, affects the secretion of aldosterone, which both affects the salt and fluid balance, but also influences how sexy we feel! But remember - sunburn is in no way sexy.
Enjoy the sun wisely.
Btw: the picture is from a vacation last year. I should probably book another sunny vacation – for health reasons, of course.